The overall goal of this proposal is to study antigen specific suppressor cells in stage I resected non small cell lung cancer patients receiving BCG immunotherapy. First, mononuclear cell subpopulations (B, T, Tm, Tg, and monocytes) will be separated on the basis of Fc receptors and assayed for responsiveness in vitro to PPD. The interactions of these subpopulations in various patient groups will be studied. Second, the in vivo induction of suppressor cells in patients who are PPD reactive who receive BCG will be examined. Third, the in vitro induction of suppressor cells will be studied. Peripheral blood mononuclear cells from patients will be co-cultured with PPD and the generation of antigen induced suppressors will be assayed. The presence and/or activity of these suppressor cells will be correlated prospectively with clinical outcome. These assays will also be performed in patients who have recurrent tumor to evaluate the mechanism of tumor-induced immunosuppression utilizing PPD as a specific antigenic marker. Correlations of specific in vitro effects such as suppressor cell function with patient outcome will lead to more effective clinical use of biological response modifiers.